I just recently let my grandson play out front as it's pretty much enclosed. I sit by the window or open door and he knows grandma MUST see him @ all times. He's a super kid and never breaks rules like this. He plays on the grass, takes pictures, sits outside the door, and runs around. I either have to see him or hear him nearby. I ALWAYS know exactly what he's doing & where he is. If i have to use the bathroom, he comes in for that time. I'm just now allowing him to play in the space mentioned, instead of hauling a big old chair out there. We've had all the talks. The key is---i either see or hear him @ all times.
Absolutely not. A 5 year old doesn't even begin to have the capacity to be on its own like that. They could hurt themselves and not be able to fix it. They could end up being kidnapped. They could wander too far out and get lost out near traffic. If social services found out that somebody was letting their 5 year old out alone like that, that child would be taken away from the parents.